Although fossil fuels still have a wide application and high demand, they have limitations due to their finite reserve, their combustion produce carbon dioxide and thus contribute to global warming.
More abundant heavy oils increasingly are becoming a source of fuels and raw materials in various fields, such as the transportation sector, chemical, petrochemical, plastics, and rubber industries. The utilization and upgrading of heavy oils to higher value products is of great significance. Extensive heavy oil sources include much of the reserves in Venezuela, tar sands in Western Canada, shale oils in the Rocky Mountains, etc. Economic recovery and utilization of these reserves represent however, significant challenges.
The present invention discloses a new way to utilize heavy oil sources to produce methanol and derived products to be used in the context of the “methanol economy”. Fossil fuel sources such as petroleum oil, natural gas and coal can be converted by known processes, including our previously disclosed patent applications into methanol and dimethyl ether by chemical recycling of carbon dioxide. Methanol and dimethyl ether are used as transportation fuels, as substitutes for gasoline and diesel fuel in ICE-powered vehicles with some needed modifications to the existing engines and fuel systems, as well as in fuel cells. By contrast with hydrogen, methanol storage and use does not require any new infrastructure including expensive pressurization and liquefaction. Because it is a liquid at room temperature, it can be easily handled, stored, distributed and used in vehicles. It is also an ideal hydrogen carrier for fuel cells and can be used in direct oxidation methanol fuel cells (DMFC). Dimethyl ether although a gas at room temperature, can be easily stored under modest pressure and used effectively as substitute for diesel fuels, liquefied natural gas (LNG) liquefied petroleum gas (LPG) and household gas.
In addition to use as fuels, methanol, dimethyl ether and their derived products have significant applications and uses. They are starting materials for varied chemical products including their catalytic conversion to olefins such as ethylene and propylene with smaller amounts of butenes, higher olefins, alkanes, and aromatics. They are thus convenient starting materials for synthetic hydrocarbons and their products.
Methanol can also be used as a source of single cell proteins. A single cell protein (SCP) refers to a protein produced by a microorganism, which degrades hydrocarbon substrates while gaining energy. The protein content depends on the type of microorganism, e.g., bacteria, yeast, mold, etc. SCP's have many uses, including as food and animal feed.
Considering the wide uses of methanol and dimethyl ether, it is clearly desirable to have improved and efficient methods for their production. The usual processing of heavy oils derived from unconventional sources such as tar sands, shale oils, etc. is costly, highly energy consuming and usually possible only in specific refineries. Thus, improvements in the processing, transportation and storage of heavy oils are desired and these are now provided by the present invention.